Vehicle occupant restraint systems having an actuatable restraint are well known in the art. One particular type of actuatable restraint system includes an inflatable restraint module. An inflatable restraint of the module is commonly referred to as an air bag, and is mounted to inflate within the occupant compartment of the vehicle. The restraint module has a source of inflation fluid and an electrically actuatable igniter, referred to as a squib.
The occupant restraint system further includes a collision/crash sensor for sensing the occurrence of a vehicle crash condition and for providing an electrical signal indicative of the crash condition. When the sensor indicates that the vehicle is in a crash condition requiring inflation of the air bag to help protect a vehicle occupant ("a deployment crash condition"), an electric current of sufficient magnitude and duration is passed through the squib for the purpose of igniting the squib. The squib, when ignited, activates the source of inflation fluid (e.g., ignition of a combustible gas or heat generating composition and/or opening of a container of pressurized gas). The source of inflation fluid is operatively coupled to the air bag, and, when activated, inflates the air bag.
Several known occupant restraint systems include an occupant position sensor and a controller, which controls the associated restraint module in response to a sensed position of a vehicle occupant. The occupant position sensor for such a system is an ultrasonic sensor, an infrared sensor, or a seating sensor. In response to the sensed occupant position, the timing of air bag deployment, the pressure of the inflated air bag, aiming of the air bag, and/or disabling the air bag are controlled. These adjustable aspects, collectively, adjust the dynamic profile of the air bag. A restraint system with adjustable aspects is commonly referred to as a "smart" restraint system.
One example of a system with an adjustable dynamic profile is disclosed in U.S. Pat. No. 5,232,243 to Blackburn et al. and assigned to the assignee of the present application. This patent discloses that it is not always desirable to inflate an air bag with 100% of the inflation fluid (e.g., gas) provided from an inflation fluid source. The system disclosed by Blackburn et al. controls the amount of gas that inflates the air bag in response to the detected weight of the occupant. Another system disclosed in U.S. Pat. No. 5,330,226 to Gentry et al., and assigned to the assignee of the present application, controls the amount of gas that inflates an air bag in response to detected occupant position.